In this work, Cu–Sn–TiO₂ composite coatings were electrochemically obtained from a sulfate bath containing 0–10 g/L of TiO₂ nanoparticles. The effect of TiO₂ particles on kinetics of cathodic electrodeposition has been studied by linear sweep voltammetry and chronopotentiometry. As compared to the Cu–Sn alloy, the Cu–Sn–TiO₂ composite coatings show rougher surfaces with TiO₂ agglomerates embedded in the metal matrix. The highest average amount of included TiO₂ is 1.7 wt.%, in the case of the bath containing 5 g/L thereof. Composite coatings showed significantly improved antibacterial properties towards E. coli ATCC 8739 bacteria as compared to the Cu–Sn coatings of the same composition. Such improvement has been connected with the corrosion resistance of the composites studied by linear polarization and electrochemical impedance spectroscopy. In the bacterial media and 3% NaCl solutions, Cu–Sn–TiO₂ composite coatings have lower corrosion resistance as compared to Cu–Sn alloys, which is caused by the nonuniformity of the surface.

Disinfection of surfaces with various functional purposes is a relevant measure for the inactivation of microorganisms and viruses. This procedure is used almost universally, from water treatment facilities to medical institutions and public spaces. Some of the most common disinfectants the World Health Organization recommends are chlorine-containing compounds. Sodium and calcium hypochlorites are only used for disinfection of the internal surfaces of water treatment facilities. However, it is known that ozone is a more powerful oxidizing agent. This study compares the effectiveness of inactivating yeast-like fungi Candida albicans, Gram-positive Bacillus subtilis, and Gram-negative bacteria Escherichia coli with aqueous ozone and sodium hypochlorite solutions. This study used ozone solutions in water with a concentration of 0.5–1.5 mg/L and sodium hypochlorite solutions with an active chlorine concentration of 50–150 mg/L. Steel and polymeric plates were used as substrates. Comparison of the CT (concentration by time) criterion at the ratio of LD50 in NaClO to ozonated water shows that the smallest difference, around 100 times, was observed in the inactivation of Candida albicans. The maximum difference is up to 230 times in the inactivation of Bacillus subtilis.

The purpose of our study was to synthesize and analyze the structure, qualitative and quantitative composition, and protective properties of phosphate-containing conversion coatings on WE43, ZRE1, and QE22 magnesium alloys doped with rare earth elements in the Hank’s Balanced Salt Solution. Scanning electron microscopy, energy dispersive X-ray analysis, and X-ray phase analysis methods were used to study the morphology, microstructure, the elemental and phase compositions of QE22, ZRE1, and WE43 magnesium alloys doped with rare earth elements, as well as conversion coatings formed on their surface during phosphating. Linear voltammetry and electrochemical impedance spectroscopy were used to study the kinetic properties of corrosion of the analyzed samples in the Hank’s Balanced Salt Solution (рН = 7.4) imitating the human body environment before and after phosphating. The study showed that the phosphating of magnesium alloys doped with rare earth elements results in the formation of low-soluble fine-grained coatings with a pronounced crystal structure and a thickness from 16 to 21 μm. The obtained conversion coatings are characterized by the following elemental composition: Са ≈ 40 wt.%; Р ≈ 15 wt.%; and О ≈ 35 wt.%. The crystal structure of phosphate-containing coatings is presented by the brushite phase (CaHPO4·2H2O). The electrochemical studies of the corrosion behavior of magnesium alloys in the model Hank’s Balanced Salt Solution (рН = 7.4) demonstrated that the corrosion current density decreases in the sequence QE22, ZRE1, WE43 and is icorr, A/cm2: 5.2·10–5; 2.5·10–5; 2.0·10–5. The obtained conversion coatings based on brushite reduce the corrosion rate of QE22, ZRE1,and WE43 magnesium alloys by 15.2, 7.8, and 6.3 times, respectivel